The duals have 1 bulb for both high/low, it's an h13 bulb. There is no way to keep "both" on as the bulb turns off one filament and turns on another for the high in the same bulb.
The quads have a bulb for low (h11) and a bulb for high (9005). Inside the housing it has a splitter. The trucks computer needs to be reflashed with a certain sales code to allow both high and low to stay on together.
http://shop.retroshop.us/ProductDetails.asp?ProductCode=Diode
Diode splitter - used in 4th gen Quad setup to keep high beams on with the low beams. For use with relay harness applications only.
For trucks originally equipped with the Dual headlamps, moved to the Quads (or '13+ Projectors) and want to keep the lows on with highs.
FOR HID LOW BEAM USE ONLY. Do not use on halogen low beams!
Sent from hell via TapATalk